lump on gold fish mouth

Question
My goldfish has a lump on his mouth...he's not eating either...what could this be?

Answer
Hi Jeanne;

Make a water change right away to help his immune system. If the tank has a filter, change 25%. If the tank has no filter, change 100%. Make sure the new water is the same temperature as the old water and use a water conditioner too. If you could give me a bit more info;

What does the lump look like? Red, whitish, fuzzy, clear?
Does he have any other symptoms? spots? bulging belly or eyes?
How big is he?
How big is the lump?
What size tank is he in?
How long has the tank been set up?
How often is the water changed?
How much water at a time is changed?

Does the tank water look okay? Clear? Is it smelly?

Let me know as soon as you can......

At Your Service;
Chris Robbins